/*

 * decript.c
 *
 *  Created on: 2013-2-22
 *      Author: root
 */

#include "decript.h"
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>

// initial permutation IP
const static char IP_Table[64] =
{
    58, 50, 42, 34, 26, 18, 10, 2, 60, 52, 44, 36, 28, 20, 12, 4,
    62, 54, 46, 38, 30, 22, 14, 6, 64, 56, 48, 40, 32, 24, 16, 8,
    57, 49, 41, 33, 25, 17,  9, 1, 59, 51, 43, 35, 27, 19, 11, 3,
    61, 53, 45, 37, 29, 21, 13, 5, 63, 55, 47, 39, 31, 23, 15, 7
};
// final permutation IP^-1
const static char IPR_Table[64] =
{
    40, 8, 48, 16, 56, 24, 64, 32, 39, 7, 47, 15, 55, 23, 63, 31,
    38, 6, 46, 14, 54, 22, 62, 30, 37, 5, 45, 13, 53, 21, 61, 29,
    36, 4, 44, 12, 52, 20, 60, 28, 35, 3, 43, 11, 51, 19, 59, 27,
    34, 2, 42, 10, 50, 18, 58, 26, 33, 1, 41,  9, 49, 17, 57, 25
};
// expansion operation matrix
static const char E_Table[48] =
{
    32,  1,  2,  3,  4,  5,  4,  5,  6,  7,  8,  9,
    8,  9, 10, 11, 12, 13, 12, 13, 14, 15, 16, 17,
    16, 17, 18, 19, 20, 21, 20, 21, 22, 23, 24, 25,
    24, 25, 26, 27, 28, 29, 28, 29, 30, 31, 32,  1
};
// 32-bit permutation function P used on the output of the S-boxes
const static char P_Table[32] =
{
    16, 7, 20, 21, 29, 12, 28, 17, 1,  15, 23, 26, 5,  18, 31, 10,
    2,  8, 24, 14, 32, 27, 3,  9,  19, 13, 30, 6,  22, 11, 4,  25
};
// permuted choice table (key)
const static char PC1_Table[56] =
{
    57, 49, 41, 33, 25, 17,  9,  1, 58, 50, 42, 34, 26, 18,
    10,  2, 59, 51, 43, 35, 27, 19, 11,  3, 60, 52, 44, 36,
    63, 55, 47, 39, 31, 23, 15,  7, 62, 54, 46, 38, 30, 22,
    14,  6, 61, 53, 45, 37, 29, 21, 13,  5, 28, 20, 12,  4
};
// permuted choice key (table)
const static char PC2_Table[48] =
{
    14, 17, 11, 24,  1,  5,  3, 28, 15,  6, 21, 10,
    23, 19, 12,  4, 26,  8, 16,  7, 27, 20, 13,  2,
    41, 52, 31, 37, 47, 55, 30, 40, 51, 45, 33, 48,
    44, 49, 39, 56, 34, 53, 46, 42, 50, 36, 29, 32
};
// number left rotations of pc1
const static char LOOP_Table[16] =
{
    1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1
};
// The (in)famous S-boxes
const static char S_Box[8][4][16] =
{
    // S1
    {   {14, 4,	13,	 1,  2, 15, 11,  8,  3, 10,  6, 12,  5,  9,  0,  7},
        {0, 15,  7,  4, 14,  2, 13,  1, 10,  6, 12, 11,  9,  5,  3,  8},
        {4,  1, 14,  8, 13,  6,  2, 11, 15, 12,  9,  7,  3, 10,  5,  0},
        {15, 12,  8,  2,  4,  9,  1,  7,  5, 11,  3, 14, 10,  0,  6, 13}
    },
    // S2
    {   {15,  1,  8, 14,  6, 11,  3,  4,  9,  7,  2, 13, 12,  0,  5, 10},
        {3, 13,  4,  7, 15,  2,  8, 14, 12,  0,  1, 10,  6,  9, 11,  5},
        {0, 14,  7, 11, 10,  4, 13,  1,  5,  8, 12,  6,  9,  3,  2, 15},
        {13,  8, 10,  1,  3, 15,  4,  2, 11,  6,  7, 12,  0,  5, 14,  9}
    },
    // S3
    {   {10,  0,  9, 14,  6,  3, 15,  5,  1, 13, 12,  7, 11,  4,  2,  8},
        {13,  7,  0,  9,  3,  4,  6, 10,  2,  8,  5, 14, 12, 11, 15,  1},
        {13,  6,  4,  9,  8, 15,  3,  0, 11,  1,  2, 12,  5, 10, 14,  7},
        {1, 10, 13,  0,  6,  9,  8,  7,  4, 15, 14,  3, 11,  5,  2, 12}
    },
    // S4
    {   {7, 13, 14,  3,  0,  6,  9, 10,  1,  2,  8,  5, 11, 12,  4, 15},
        {13,  8, 11,  5,  6, 15,  0,  3,  4,  7,  2, 12,  1, 10, 14,  9},
        {10,  6,  9,  0, 12, 11,  7, 13, 15,  1,  3, 14,  5,  2,  8,  4},
        {3, 15,  0,  6, 10,  1, 13,  8,  9,  4,  5, 11, 12,  7,  2, 14}
    },
    // S5
    {   {2, 12,  4,  1,  7, 10, 11,  6,  8,  5,  3, 15, 13,  0, 14,  9},
        {14, 11,  2, 12,  4,  7, 13,  1,  5,  0, 15, 10,  3,  9,  8,  6},
        {4,  2,  1, 11, 10, 13,  7,  8, 15,  9, 12,  5,  6,  3,  0, 14},
        {11,  8, 12,  7,  1, 14,  2, 13,  6, 15,  0,  9, 10,  4,  5,  3}
    },
    // S6
    {   {12,  1, 10, 15,  9,  2,  6,  8,  0, 13,  3,  4, 14,  7,  5, 11},
        {10, 15,  4,  2,  7, 12,  9,  5,  6,  1, 13, 14,  0, 11,  3,  8},
        {9, 14, 15,  5,  2,  8, 12,  3,  7,  0,  4, 10,  1, 13, 11,  6},
        {4,  3,  2, 12,  9,  5, 15, 10, 11, 14,  1,  7,  6,  0,  8, 13}
    },
    // S7
    {   {4, 11,  2, 14, 15,  0,  8, 13,  3, 12,  9,  7,  5, 10,  6,  1},
        {13,  0, 11,  7,  4,  9,  1, 10, 14,  3,  5, 12,  2, 15,  8,  6},
        {1,  4, 11, 13, 12,  3,  7, 14, 10, 15,  6,  8,  0,  5,  9,  2},
        {6, 11, 13,  8,  1,  4, 10,  7,  9,  5,  0, 15, 14,  2,  3, 12}
    },
    // S8
    {   {13,  2,  8,  4,  6, 15, 11,  1, 10,  9,  3, 14,  5,  0, 12,  7},
        {1, 15, 13,  8, 10,  3,  7,  4, 12,  5,  6, 11,  0, 14,  9,  2},
        {7, 11,  4,  1,  9, 12, 14,  2,  0,  6, 10, 13, 15,  3,  5,  8},
        {2,  1, 14,  7,  4, 10,  8, 13, 15, 12,  9,  0,  3,  5,  6, 11}
    }
};

//////////////////////////////////////////////////////////////////////////

typedef int    (*PSubKey)[16][48];

//////////////////////////////////////////////////////////////////////////

static void DES(char Out[8], char In[8], int pSubKey[][48], int Type);//±ê×ŒDESŒÓ/œâÃÜ
static void SetSubKey(int pSubKey[][48], const char Key[8]);// ÉèÖÃ×ÓÃÜÔ¿
static void F_func(int In[32], const int Ki[48]);// f º¯Êý
static void S_func(int Out[32], const int In[48]);// S ºÐŽúÌæ
static void Transform(int *Out, int *In, const char *Table, int len);// ±ä»»
static void Xor(int *InA, const int *InB, int len);// Òì»ò
static void RotateL(int *In, int len, int loop);// Ñ­»·×óÒÆ
static void ByteToBit(int *Out, const char *In, int bits);// ×ÖœÚ×é×ª»»³ÉÎ»×é
static void BitToByte(char *Out, const int *In, int bits);// Î»×é×ª»»³É×ÖœÚ×é

//////////////////////////////////////////////////////////////////////////


//static int Is3DES;// 3ŽÎDES±êÖŸ
//static char Tmp[256];// /*deskey[16]*/;

//////////////////////////////////////////////////////////////////////////

//////////////////////////////////////////////////////////////////////////
// Code starts from Line 130
//////////////////////////////////////////////////////////////////////////
int Des_Go(char *Out, char *In, const char *Key, int Type)
{
    if( !( Out && In && Key))
    {
        return 0;
    }
    int SubKey[16][48];// 16ÈŠ×ÓÃÜÔ¿
    SetSubKey(SubKey, Key);
//	if( !Is3DES )
    {
        // 1ŽÎDES
//		for(long i = 0; i < 2; ++i,Out+=8,In+=8)
        {
            DES(Out, In, SubKey, Type);
        }
    }
    /*else
    {
    	// 3ŽÎDES ŒÓÃÜ:ŒÓ(key0)-œâ(key1)-ŒÓ(key0) œâÃÜ::œâ(key0)-ŒÓ(key1)-œâ(key0)
    	for(long i=0,j=datalen>>3; i<j; ++i,Out+=8,In+=8) {
    		DES(Out, In,  &SubKey[0], Type);
    		DES(Out, Out, &SubKey[1], !Type);
    		DES(Out, Out, &SubKey[0], Type);
    	}
    }*/
    return 1;
}
void DES(char Out[8], char In[8], int pSubKey[][48], int Type)
{
    int M[64], tmp[32], *Li=&M[0], *Ri=&M[32];
    ByteToBit(M, In, 64);
    Transform(M, M, IP_Table, 64);
    int i;
    if( Type == ENCRYPT )
    {
        for(i=0; i<16; ++i)
        {
            memcpy(tmp, Ri, 32 * sizeof(int));
            F_func(Ri, pSubKey[i]);
            Xor(Ri, Li, 32);
            memcpy(Li, tmp, 32 * sizeof(int));
        }
    }
    else
    {
        for(i=15; i>=0; --i)
        {
            memcpy(tmp, Li, 32 * sizeof(int));
            F_func(Li, pSubKey[i]);
            Xor(Li, Ri, 32);
            memcpy(Ri, tmp, 32 * sizeof(int));
        }
    }
    Transform(M, M, IPR_Table, 64);
    BitToByte(Out, M, 64);
}
void SetSubKey(int pSubKey[][48], const char Key[8])
{
    int K[64], *KL=&K[0], *KR=&K[28];
    ByteToBit(K, Key, 64);
    Transform(K, K, PC1_Table, 56);
    int i = 0;
    for(i=0; i<16; ++i)
    {
        RotateL(KL, 28, LOOP_Table[i]);
        RotateL(KR, 28, LOOP_Table[i]);
        Transform(pSubKey[i], K, PC2_Table, 48);
    }
}
void F_func(int In[32], const int Ki[48])
{
    int MR[48];
    Transform(MR, In, E_Table, 48);
    Xor(MR, Ki, 48);
    S_func(In, MR);
    Transform(In, In, P_Table, 32);
}
void S_func(int Out[32], const int In[48])
{
    int i, j, k;
    for(i=0,j,k; i<8; ++i,In+=6,Out+=4)
    {
        j = (In[0]<<1) + In[5];
        k = (In[1]<<3) + (In[2]<<2) + (In[3]<<1) + In[4];
        //printf("%d, %d, %d\n", i, j, k);
        ByteToBit(Out, &S_Box[i][j][k], 4);
    }
}
void Transform(int *Out, int *In, const char *Table, int len)
{
    int Tmp[256];
    int i = 0;
    for(i=0; i<len; ++i)
    {
        Tmp[i] = In[ Table[i]-1 ];
    }
    memcpy(Out, Tmp, len * sizeof(int));
}
void Xor(int *InA, const int *InB, int len)
{
    int i = 0;
    for(i=0; i<len; ++i)
        InA[i] ^= InB[i];
}
void RotateL(int *In, int len, int loop)
{
    int Tmp[256];
    int i;
    memcpy(Tmp, In, loop * sizeof(int));

    for (i = 0; i < len - loop; i++)
    {
        In[i] = *(In + loop + i);
    }
    //memcpy(In, In+loop, (len-loop) * sizeof(int));
    memcpy(In+len-loop, Tmp, loop * sizeof(int));
}
void ByteToBit(int *Out, const char *In, int bits)
{
    int i = 0;
    for(i = 0; i < bits; ++i)
    {
        Out[i] = (In[i>>3] >> (i & 7)) & 1;
        //printf("iii: %d, %X, %d\n", i, Out[i], In[i>>3]);
    }
}
void BitToByte(char *Out, const int *In, int bits)
{
    memset(Out, 0, bits>>3);
    int i = 0;
    for(i=0; i<bits; ++i)
        Out[i>>3] |= In[i]<<(i&7);
}
